This is a resubmission of an NIMH Mentored Research Scientist Development Award (K01) entitled Functional Characterization of Risk Variants for Psychotic Illness in the GWAS Era. (1 K01 MH086714-01) It was reviewed by the Behavioral Genetics and Epidemiology Study Section in February 2009 and received a priority score of 239. This award offers an important opportunity to prepare the candidate to achieve her long term career goal: to carry out translational psychiatric genetics research independently and to contribute to the understanding of how genetic variations influence on neural functions that contribute to the development of psychotic illnesses. The candidate's interest is in psychiatric genetics, with a particular focus on elucidating the etiologic pathways from DNA variants to the abnormal brain function that characterizes psychotic illness. The primary focus of the investigator's training during the award period will be in molecular genetics, genomics, and bioinformatics, which are areas where the investigator has not had formal training but will be essential to develop expertise for her proposed investigation and for her transition to be an independent investigator. The extensive hands-on training activities will allow the candidate to design and conduct genetic experiments and analyses independently by the end of the award period and have a high likelihood of success for submitting a R01 research project in the future. The candidate is an instructor at McLean Hospital, Harvard Medical School. Her proposed research project will be carried out at the Cognitive Neuroscience Laboratory (Director: Dr. Dean Salisbury, advisor on this application) McLean Hospital and at the Psychiatric and Neurodevelopmental Genetics Unit (Dr. Jordan Smoller, mentor of this application) Harvard Medical School. Previous studies indicate that four neurophysiologic traits (i.e., P300 amplitude and latency, P50 inhibition, and Gamma band response) are putative endophenotypes for psychotic illness and capture three important domains of brain function. The goals of this study are to use these quantitative endophenotypes to characterize the neurophysiological effects of disease susceptibility variants identified by genomewide association studies by mapping their effects on three key domains of brain function. First, the candidate will collect DNA samples and neurophysiological trait data from a sample of patients with psychotic illness and control subjects to provide a resource for endophenotype-mapping. Second, at the behavior level, she will examine cortical neural network dysfunction as measured by gamma-band response (GBR) in schizophrenia and psychotic bipolar patients to further clarify the overlapping and distinct profiles of GBR for these two disorders. Third, at the molecular genetic level, she will select risk variants that have shown the strongest evidence of association with clinical phenotypes of bipolar disorder (BPD), schizophrenia (SCZ), or psychosis, in completed GWAS analyses, and examine their association with quantitative endophenotypes to address key questions about the specific functional domains influenced by these risk variants. She will also genotype markers that have been significantly associated with schizophrenia linked endophenotypes in the large Consortium on the Genetics of Schizophrenia (COGS) study to replicate the findings that emerge from the COGS among SCZ patients and extend them to examine functional effects in psychotic bipolar patients.